DESCRIPTION: (Investigator's abstract): The epibranchial placodes in embryonic vertebrates are known to give rise to the sensory ganglionic cells of the facial, glossopharyngeal and vagal nerves that innervate taste buds, but the embryonic origins of taste buds, as well as the tissues that induce epibranchial placodes, remain unknown. Using new data on the development of the octavolateralis system, a new model of the development of the gustatory system is proposed. According to this model, epibranchial placodes are induced by chordamesoderm and/or paraxial mesoderm, and these placodes give rise to the progenitors of both taste buds adn sensory ganglionic cells. In order to test this model, extirpation and homotopic explanation of intracellularly labeled tissues involving chordamesoderm, epibranchial placodes, neural crest and neural plate are proposed. The experiments will be performed on embryonic axolotls, as the necessarily large number of embryos can be easily obtained, and these embryos are sufficiently robust to tolerate the experimental manipulations. Additional experimental neuroanatomical studies on the organization of the gustatory system of juvenile and adult axolotls will also be conducted in order to provide a more complete picture of this system.